| Date | Wed, 3 Dec 2008 11:52:50 -0800 | From | Greg KH <> | Subject | [patch 057/104] powerpc/spufs: Fix spinning in spufs_ps_fault on signal |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: Jeremy Kerr <jk@ozlabs.org>
commit 606572634c3faa5b32a8fc430266e6e9d78d2179 upstream.
Currently, we can end up in an infinite loop if we get a signal while the kernel has faulted in spufs_ps_fault. Eg:
alarm(1);
write(fd, some_spu_psmap_register_address, 4);
- the write's copy_from_user will fault on the ps mapping, and signal_pending will be non-zero. Because returning from the fault handler will never clear TIF_SIGPENDING, so we'll just keep faulting, resulting in an unkillable process using 100% of CPU.
This change returns VM_FAULT_SIGBUS if there's a fatal signal pending, letting us escape the loop.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/powerpc/platforms/cell/spufs/file.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/powerpc/platforms/cell/spufs/file.c +++ b/arch/powerpc/platforms/cell/spufs/file.c @@ -390,6 +390,9 @@ static int spufs_ps_fault(struct vm_area if (offset >= ps_size) return VM_FAULT_SIGBUS; + if (fatal_signal_pending(current)) + return VM_FAULT_SIGBUS; + /* * Because we release the mmap_sem, the context may be destroyed while * we're in spu_wait. Grab an extra reference so it isn't destroyed
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